From these two, I would most probably go for the Joolz. They make their frames much, much more durable, so the longevity will be better - and not only because of the frame quality but also because of the slightly larger seat with an extendable leg rest. Although a bit bulky, the Day Plus is also nicer to push and, overall, a better value for money from my experience.
The Reef is a nice-looking pram, but the engineering doesn't match the price, in my opinion, and the seat is really short. So the Joolz would be my go-to out of these two. Hope I helped!